Molluscan Shellfish Growing Water Coliform Test


PHL Location

Central Laboratory, Lake Charles Laboratory, Shreveport Laboratory

CPT Code



Shellfish Growing Water Test, Oyster Water Test

Brief Description of Test

Samples are analyzed using A-1-M method to enumerate the number of fecal coliforms. Sample salinity is also determined

Possible Results

Fecal coliform Most Probable Number (MPN)/100ml; salinity in ppt.

Reference Range

<2 - >1600/ml

Specimen Type

Shellfish growing waters

Specimen Container(s):

Clean, sterile, non-toxic bottles.

Minimum volume accepted:

100 ml

Collection Instructions

Follow procedures as described in the Louisiana Sanitarian manual. A temperature sample must be taken when collecting the initial sample (TC1) and a temperature sample must be taken when taking the final sample (TC2). All labeling must be written legibly in water proof ink.

Storage and Transport Instructions

Samples should be transported in an iced cooler. Samples should be received into the laboratory at or below 10°C and must be tested within 30 hours.

Note:  If a sample is not at or below 10°C upon receipt, because of high water temperature, and time between the sample being taken and sample receipt into lab, then this will be taken into account.  The sample should be of a lesser temperature than the water temperature in the field.

Causes for Rejection

§         Sample is submitted >30 hours old.

§         Sample is submitted in a frozen state.

§         Sample is submitted with no identification or missing collection date or time.

§         Sample is submitted in an unsatisfactory container or is leaking.

§         Insufficient sample volume is submitted .

§         Water sample is >10°C upon receipt.

Limitations of the Procedure

Overgrowth by non-coliform bacteria.

Interfering Substances

Coliforms may be found with the absence of E. coli.


  1. QA Manual Laboratory Analysis of Shellfish and Shellfish Growing Waters. 2004. Louisiana Department of Health and Hospitals, Office of Public Health, Laboratory Services. New Orleans, Louisiana.
  2. Recommended Procedures for the Examination of Sea Water and Shellfish, 4th ed. 1970. American Public Health Association, Inc. New York, N.Y.

Additional Information

Environmental conditions (tide, weather, wind direction and speed) are recorded. Complete LAB 49 submission form. Two temperature control blanks are used to determine temperature upon receipt in the laboratory.